CLINICAL ANATOMY
OF THE UPPER LIMB
7. 2. 2013
Kaan Yücel
M.D., Ph.D.
http://yeditepeanatomy1.org
Key word for this class
[Nerve] Entrapment [/Compression]
A TOTAL OF 8 FIGURES IN THE TEXT
Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
AXILLA
Enlargement of Axillary Lymph Nodes
An infection in the upper limb can cause the axillary nodes to enlarge and become tender and inflamed,
a condition called lymphangitis (inflammation of lymphatic vessels). The humeral group of nodes is usually the
first to be involved.In metastatic cancer of the apical group, the nodes often adhere to the axillary vein, which
may necessitate excision of part of this vessel. Enlargement of the apical nodes may obstruct the cephalic vein
superior to the pectoralis minor. The examination of the axillary lymph nodes always forms part of the clinical
examination of the breast.
With the patient standing or sitting, he or she is asked to place the hand of the side to be examined on
the hip and push hard medially. This action of adduction of the shoulder joint causes the pectoralis major
muscle to contract maximally so that it becomes hard like a board. The examiner then palpates the axillary
nodes.
Arterial Innervation and Raynaud’s Disease
The arteries of the upper limb are innervated by sympathetic nerves. The preganglionic fibers originate
from cell bodies in the second to eighth thoracic segments of the spinal cord. They ascend in the sympathetic
trunk and synapse in the middle cervical, inferior cervical, first thoracic,or stellate ganglia. The postganglionic
fibers join the nerves that form the brachial plexus and are distributed to the arteries within the branches of
the plexus. For example, the digital arteries of the fingers are supplied by postgan glionic sympathetic fibers
that run in the digital nerves. Vasospastic diseases involving digital arterioles, such as Raynaud’s disease, may
require a cervicodorsal preganglionic sympathectomy to prevent necrosis of the fingers. The operation is
followed by arterial vasodilatation, with consequent increased blood flow to the upper limb.
Aneurysm of Axillary Artery
The first part of the axillary artery may enlarge (aneurysm of the axillary artery) and compress the trunks of the
brachial plexus, causing pain and anesthesia (loss of sensation) in the areas of the skin supplied by the affected
nerves.
Spontaneous Thrombosis of the Axillary Vein
Spontaneous thrombosis of the axillary vein occasionally occurs after excessive and unaccustomed movements
of the arm at the shoulder joint.
BRACHIAL PLEXUS
Dermatomes and Cutaneous Nerves of the Upper Limb
It may be necessary for a physician to test the integrity of the spinal cord segments of C3 through T1. It
is seen that the dermatomes for the upper cervical segments C3 to 6 are located along the lateral margin of the
upper limb; the C7 dermatome is situated on the middle finger; and the dermatomes for C8, T1, and T2 are
along the medial margin of the limb. The nerve fibers from a particular segment of the spinal cord, although
they exit from the cord in a spinal nerve of the same segment, pass to the skin in two or more different
cutaneous nerves.
The skin over the point of the shoulder and halfway down the lateral surface of the deltoid muscle is
supplied by the supraclavicular nerves (C3 and 4). Pain may be referred to this region as a result of
inflammatory lesions involving the diaphragmatic pleura or peritoneum. The afferent stimuli reach the spinal
cord via the phrenic nerves (C3, 4, and 5). Pleurisy, peritonitis, subphrenic abscess, or gallbladder disease may
therefore be responsible for shoulder pain.
Tendon Reflexes and the Segmental Innervation of Muscles of the Upper Limb
The skeletal muscle receives a segmental innervation. Most muscles are innervated by several spinal
nerves and therefore by several segments of the spinal cord. A physician should know the segmental
innervation of the following muscles because it is possible to test them by eliciting simple muscle reflexes in the
patient:
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
 Biceps brachii tendon reflex: C5 and 6 (flexion of the elbow joint by tapping the biceps tendon)
 Triceps tendon reflex: C6, 7, and 8 (extension of the elbow joint by tapping the triceps tendon)
 Brachioradialis tendon reflex: C5, 6, and 7 (supination of the radioulnar joints by tapping the insertion of the
brachioradialis tendon)
Brachial Plexus Injuries
Injuries to the brachial plexus affect movements and cutaneous sensations in the upper limb. Disease,
stretching, and wounds in the lateral cervical region (posterior triangle) of the neck or in the axilla may produce
brachial plexus injuries. Signs and symptoms depend on the part of the plexus involved. Injuries to the brachial
plexus result in paralysis and anesthesia.
Testing the person's ability to perform movements assesses the degree of paralysis. In complete
paralysis, no movement is detectable. In incomplete paralysis, not all muscles are paralyzed; therefore, the
person can move, but the movements are weak compared with those on the normal side. Determining the
ability of the person to feel pain (e.g., from a pinprick of the skin) tests the degree of anesthesia.
Injuries to superior parts of the brachial plexus (C5 and C6) usually result from an excessive increase in
the angle between the neck and the shoulder. These injuries can occur in a person who is thrown from a
motorcycle or a horse and lands on the shoulder in a way that widely separates the neck and shoulder. When
thrown, the person's shoulder often hits something (e.g., a tree or the ground) and stops, but the head and
trunk continue to move. This stretches or ruptures superior parts of the brachial plexus or avulses (tears) the
roots of the plexus from the spinal cord.
Chronic microtrauma to the superior trunk of the brachial plexus from carrying a heavy backpack can
produce motor and sensory deficits in the distribution of the musculocutaneous and radial nerves. A superior
brachial plexus injury may produce muscle spasms and a severe disability in hikers (backpacker's palsy) who
carry heavy backpacks for long periods.
Compression of cords of the brachial plexus may result from prolonged hyperabduction of the arm
during performance of manual tasks over the head, such as painting a ceiling. The cords are impinged or
compressed between the coracoid process of the scapula and the pectoralis minor tendon. Compression of the
axillary artery and vein causes ischemia of the upper limb and distension of the superficial veins. These signs
and symptoms of hyperabduction syndrome result from compression of the axillary vessels and nerves.
The roots, trunks, and divisions of the brachial plexus reside in the lower part of the posterior triangle of
the neck, whereas the cords and most of the branches of the plexus lie in the axilla. Complete lesions involving
all the roots of the plexus are rare. Incomplete injuries are common and are usually caused by traction or
pressure; individual nerves can be divided by stab wounds.
Upper Lesions of the Brachial Plexus (Erb-Duchenne Palsy)
Upper lesions of the brachial plexus are injuries resulting from excessive displacement of the head to
the opposite side and depression of the shoulder on the same side. This causes excessive traction or even
tearing of C5 and 6 roots of the plexus. It occurs in infants during a difficult delivery or in adults after a blow to
or fall on the shoulder. The suprascapular nerve, the nerve to the subclavius, and the musculocutaneous and
axillary nerves all possess nerve fibers derived from C5 and 6 roots and will therefore be functionless. The
following muscles will consequently be paralyzed: supraspinatus (abductor of the shoulder) and infraspinatus
(lateral rotator of the shoulder); subclavius (depresses the clavicle); biceps brachii (supinator of the forearm,
flexor of the elbow, weak flexor of the shoulder), and greater part of the brachialis (flexor of the elbow), and
the coracobrachialis (flexor of the shoulder); and the deltoid (abductor of the shoulder) and the teres minor
(lateral rotator of the shoulder). Thus, the limb will hang limply by the side, medially rotated by the unopposed
sternocostal part of the pectoralis major; the forearm will be pronated because of loss of the action of the
biceps. The position of the upper limb in this condition has been likened to that of a porter or waiter hinting for
a tip (waiter’s tip position). In addition, there will be a loss of sensation down the lateral side of the arm.
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
Lower Lesions of the Brachial Plexus (Klumpke Palsy)
Injuries to inferior parts of the brachial plexus (Klumpke paralysis) are much less common. Inferior
brachial plexus injuries, usually traction injuries, may occur when the upper limb is suddenly pulled superiorly—
for example, when a person grasps something to break a fall or a baby's upper limb is pulled excessively during
delivery. These events injure the inferior trunk of the brachial plexus (C8 and T1) and may avulse the roots of
the spinal nerves from the spinal cord. The short muscles of the hand are affected, and a claw hand occurs.
The first thoracic nerve is usually torn. The nerve fibers from this segment run in the ulnar and median
nerves to supply all the small muscles of the hand. The hand has a clawed appearance (Claw-ed hand) caused
by hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints. The extensor
digitorum is unopposed by the lumbricals and interossei and extends the metacarpophalangeal joints; the
flexor digitorum superficialis and profundus are unopposed by the lumbricals and interossei and flex the middle
and terminal phalanges, respectively. In addition, loss of sensation will occur along the medial side of the arm.
If the eighth cervical nerve is also damaged, the extent of anesthesia will be greater and will involve the medial
side of the forearm, hand, and medial two fingers.
Lower lesions of the brachial plexus can also be produced by the presence of a cervical rib or malignant
metastases from the lungs in the lower deep cervical lymph nodes.
Figure 1. Characteristic upper extremity position in Klumpke’s palsy
http://pediatric-orthopedics.org/orthopedic-conditions-from-birth-to-walking/24-birth-palsies-brachial-plexus-injuries.html
Compression of the Brachial Plexus, Subclavian Artery, and Subclavian Vein by the Clavicle
The interval between the clavicle and the first rib in some patients may become narrowed and thus is
responsible for compression of nerves and blood vessels.
Long Thoracic Nerve Injuries
The long thoracic nerve, which arises from C5, 6, and 7 and supplies the serratus anterior muscle, can be
injured by blows to or pressure on the posterior triangle of the neck or during the surgical procedure of radical
mastectomy. Paralysis of the serratus anterior results in the inability to rotate the scapula during the
movement of abduction of the arm above a right angle. The patient therefore experiences difficulty in raising
the arm above the head. The vertebral border and inferior angle of the scapula will no longer be kept closely
applied to the chest wall and will protrude posteriorly, a condition known as “winged scapula”.
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
Figure 2. “Winged scapula” following long thoracic nerve injury: There is also a video in the link
http://www.coreconcepts.com.sg/mcr/scapula-winging
Axillary Nerve Injuries
The axillary nerve, which arises from the posterior cord of the brachial plexus (C5 and 6), can be
injured by the pressure of a badly adjusted crutch pressing upward into the armpit. The passage of the axillary
nerve backward from the axilla through the quadrangular space makes it particularly vulnerable here to
downward displacement of the humeral head in shoulder dislocations or fractures of the surgical neck of the
humerus. Paralysis of the deltoid and teres minor muscles occurs.
The cutaneous branches of the axillary nerve, including the upper lateral cutaneous nerve of the arm,
are functionless, and consequently there is a loss of skin sensation over the lower half of the deltoid muscle (or
lateral part of the arm). The paralyzed deltoid wastes rapidly and the underlying greater tuberosity can be
readily palpated. Because the supraspinatus is the only other abductor of the shoulder, this movement is much
impaired. Paralysis of the teres minor is not recognizable clinically.
Impaired shoulder abduction, shoulder weakness, difficulty in lifting the objects on the side of the injury,
difficulty in lifting the arm above the head are among the clinical symptoms in addition to sensory loss in the
outer (lateral) part of the arm.
The deltoid is a common site for the intramuscular injection of drugs. The axillary nerve runs
transversely under cover of the deltoid at the level of the surgical neck of the humerus. Awareness of its
location also avoids injury to it during surgical approaches to the shoulder.
Radial Nerve Injuries
The radial nerve is commonly damaged in the axilla and in the spiral groove.
Injuries to the Radial Nerve in the Axilla
In the axilla the nerve can be injured by the pressure of the upper end of a badly fitting crutch pressing
up into the armpit or by a drunkard falling asleep with one arm over the back of a chair. It can also be badly
damaged in the axilla by fractures and dislocations of the proximal end of the humerus. When the humerus is
displaced downward in dislocations of the shoulder, the radial nerve, which is wrapped around the back of the
shaft of the bone, is pulled downward, stretching the nerve in the axilla excessively. The clinical findings in
injury to the radial nerve in the axilla are as follows.
Motor
The triceps, the anconeus, and the long extensors of the wrist are paralyzed. The patient is unable to extend
the elbow joint, the wrist joint, and the fingers. Wristdrop, or flexion of the wrist, occurs as a result of the
action of the unopposed flexor muscles of the wrist. Wristdrop is very disabling because one is unable to flex
the fingers strongly for the purpose of firmly gripping an object with the wrist fully flexed. (Try it on yourself.) If
the wrist and proximal phalanges are passively extended by holding them in position with the opposite hand,
the middle and distal phalanges of the fingers can be extended by the action of the lumbricals and interossei,
which are inserted into the extensor expansions. The brachioradialis and supinator muscles are also paralyzed,
but supination is still performed well by the biceps brachii.
Sensory
A small loss of skin sensation occurs down the posterior surface of the lower part of the arm and down a
narrow strip on the back of the forearm. A variable area of sensory loss is present on the lateral part of the
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
dorsum of the hand and on the dorsal surface of the roots of the lateral three and a half fingers. The area of
total anesthesia is relatively small because of the overlap of sensory innervation by adjacent nerves.
Trophic Changes
Trophic changes are slight.
Figure 3. Wrist drop
http://imueos.wordpress.com/2010/09/27/bones-of-upper-limb-lower-limb-and-vertebrae-part-2
Injuries to the Radial Nerve in the Spiral Groove of the Humerus
In the spiral groove of the humerus, the radial nerve can be injured at the time of fracture of the shaft of
the humerus or subsequently involved during the formation of the callus. The pressure of the back of the arm
on the edge of the operating table in an unconscious patient has also been known to injure the nerve at this
site. The prolonged application of a tourniquet to the arm in a person with a slender triceps muscle is often
followed by temporary radial palsy. The clinical findings in injury to the radial nerve in the spiral groove are as
follows:
The injury to the radial nerve occurs most commonly in the distal part of the groove, beyond the origin of the
nerves to the triceps and the anconeus and beyond the origin of the cutaneous nerves.
Motor: The patient is unable to extend the wrist and the fingers, and wristdrop occurs.
Sensory: A variable small area of anesthesia is present over the dorsal surface of the hand and the dorsal
surface of the roots of the lateral three and a half fingers.
Trophic changes: These are very slight or absent.
Radial Tunnel Syndrome
Radial tunnel syndrome is a pain syndrome resulting from compression of the posterior interosseous
nerve at the proximal forearm. Some claim that the radial tunnel syndrome is actually the earlier form of a
posterior interosseus nerve injury.
Radial tunnel syndrome is a condition that can cause aching in the forearm just below the elbow. It has
no specific radiologic or electrodiagnostic findings. Radial tunnel syndrome can be difficult to diagnose because
the tests that are available to look for the problem are not very accurate. This means that the diagnosis is made
on the history that you give and the physical exam (anatomy knowledge!).
The radial nerve runs behind the arm and crosses the elbow on the outside as it travels down the
forearm into the hand. The radial tunnel is a potential space located anterior to the proximal radius through
which the posterior interosseus nerve passes. The tunnel extends for approximately 5 cm starting from the
level of the humeroradial joint and extending past the proximal edge of the supinator.
Patients with radial tunnel syndrome usually present with pain along the dorsoradial aspect of the
proximal forearm. The pain may radiate proximally and distally. The pain has a tendency to increase with
rotational activities of the forearm. There is tenderness and pain at the lateral side of the elbow. The
symptoms of radial tunnel syndrome can be confused with lateral epicondylitis (tennis elbow). Although the
cause is different, the symptoms of radial tunnel syndrome are very similar to lateral epicondylitis, or tennis
elbow. The symptoms of radial tunnel syndrome get worse with using the arm - just like tennis elbow. The pain
is on the outside of the elbow - just like tennis elbow. The one difference is that the place where the elbow is
most tender is slightly different.
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
In tennis elbow, the tenderness is mostly right where the tendon attaches to the lateral epicondyle of the
elbow. In radial tunnel syndrome, the place that is most tender is about two inches further down the arm, right
over where the radial nerve goes into the supinator muscle.
More @ http://www.kwoc.net/radial%20tunnel%20syndrome.pdf
Is it Tennis Elbow or Radial Tunnel?
http://www.dynamicchiropractic.com/mpacms/dc/article.php?id=38691
Naam NH, Nemani S. Radial tunnel syndrome. Orthop Clin North Am. 2012 Oct;43(4):529-36.
Injuries to the Deep Branch of the Radial Nerve
The deep branch of the radial nerve is a motor nerve to the extensor muscles in the posterior
compartment of the forearm. It can be damaged in fractures of the proximal end of the radius or during
dislocation of the radial head. The nerve supply to the supinator and the extensor carpi radialis longus will be
undamaged, and because the latter muscle is powerful, it will keep the wrist joint extended, and wristdrop will
not occur. No sensory loss occurs because this is a motor nerve.
Injuries to the Superficial Radial Nerve
Division of the superficial radial nerve, which is sensory, as in a stab wound, results in a variable small
area of anesthesia over the dorsum of the hand and the dorsal surface of the roots of the lateral three and a
half fingers.
Musculocutaneous Nerve Injuries
The musculocutaneous nerve is rarely injured because of its protected position beneath the biceps
brachii muscle. This uncommon injury might be caused by a weapon such as a knife.
If it is injured high up in the arm, the biceps and coracobrachialis are paralyzed and the brachialis muscle
is weakened (the latter muscle is also supplied by the radial nerve). Weak flexion may occur at the
glenohumeral (shoulder) joint owing to the injury of the musculocutaneous nerve affecting the long head of the
biceps brachii and the coracobrachialis. Flexion of the elbow joint and supination of the forearm are greatly
weakened but not lost. Flexion of the forearm at the elbow joint is then produced by the remainder of the
brachialis muscle and the flexors of the forearm. Weak supination is also still possible, produced by the
supinator, which is supplied by the radial nerve.
There is also sensory loss along the lateral side of the forearm. Wounds or cuts of the forearm can sever
the lateral cutaneous nerve of the forearm, a continuation of the musculocutaneous nerve beyond the cubital
fossa, resulting in sensory loss along the lateral side of the forearm.
Median Nerve Injuries
From a clinical standpoint, the median nerve is injured occasionally in the elbow region in supracondylar
fractures of the humerus. It is most commonly injured by stab wounds or broken glass just proximal to the
flexor retinaculum;here it lies in the interval between the tendons of the flexor carpi radialis and flexor
digitorum superficialis, overlapped by the palmaris longus. The clinical findings in injury to the median nerve
are as follows.
Injuries to the Median Nerve at the Elbow
Motor
The pronator muscles of the forearm and the long flexor muscles of the wrist and fingers, with the
exception of the flexor carpi ulnaris and the medial half of the flexor digitorum profundus, will be paralyzed. As
a result, the forearm is kept in the supine position; wrist flexion is weak and is accompanied by adduction. The
latter deviation is caused by the paralysis of the flexor carpi radialis and the strength of the flexor carpi ulnaris
and the medial half of the flexor digitorum profundus.
Flexion of the proximal interphalangeal joints of the 1st-3rd digits is lost and flexion of the 4th and 5th digits is
weakened. Flexion of the distal interphalangeal joints of the 2nd and 3rd digits is also lost.
The ability to flex the metacarpophalangeal joints of the 2nd and 3rd digits is affected because the digital
branches of the median nerve supply the 1st and 2nd lumbricals (although the interossei will help in that,
making the metacparhophalangeal joints of these two fingers weak rather than impossible).
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
Hand of Benediction (Pope’s Blessing)
When the patient tries to make a fist, the index and to a lesser extent the middle fingers tend to remain
straight (partially extended), whereas the ring and little fingers flex during the formation of the fist. The latter
two fingers are, however, weakened by the loss of the flexor digitorum superficialis.
Ape hand deformity
Thenar muscle function (function of the muscles at the base of the thumb) is also lost, as in carpal tunnel
syndrome. Flexion of the terminal phalanx of the thumb is lost because of paralysis of the flexor pollicis longus.
The muscles of the thenar eminence are paralyzed and wasted so that the eminence is flattened. The thumb is
laterally rotated and adducted. The hand looks flattened and “ape-like”.
Sensory
Skin sensation is lost on the lateral half or less of the palm of the hand and the palmar aspect of the
lateral three and a half fingers. Sensory loss also occurs on the skin of the distal part of the dorsal surfaces of
the lateral three and a half fingers.
Vasomotor Changes
The skin areas involved in sensory loss are warmer and drier than normal because of the arteriolar dilatation
and absence of sweating resulting from loss of sympathetic control.
Trophic Changes
In long-standing cases, changes are found in the hand and fingers. The skin is dry and scaly, the nails crack
easily, and atrophy of the pulp of the fingers is present.
Injuries to the Median Nerve at the Wrist
Motor: The muscles of the thenar eminence are paralyzed and wasted so that the eminence becomes
flattened. The thumb is laterally rotated and adducted. The hand looks flattened and “ape-like.” Opposition
movement of the thumb is impossible. The first two lumbricals are paralyzed, which can be recognized clinically
when the patient is asked to make a fist slowly, and the index and middle fingers tend to lag behind the ring
and little fingers.
Sensory, vasomotor, and trophic changes: These changes are identical to those found in the elbow lesions.
Perhaps the most serious disability of all in median nerve injuries is the loss of ability to oppose the
thumb to the other fingers and the loss of sensation over the lateral fingers. The delicate pincer-like action of
the hand is no longer possible.
Figure 4. “Ape hand deformity” in median nerve injuries
http://2hmnzava.blogspot.com/2010/04/from-orthopaedic-dictionary.html
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
Carpal Tunnel Syndrome
The carpal tunnel, formed by the concave anterior surface of the carpal bones and closed by the flexor
retinaculum, is tightly packed with the long flexor tendons of the fingers, their surrounding synovial sheaths,
and the median nerve.
Carpal Tunnel Syndrome which is related to median nerve is the most common peripheral nerve injury
seen in the upper limb. The second most common is the cubital syndrome which is related to the ulnar nerve.
Carpal Tunnel Syndrome has been frequently been reported to be more common in females than in men.
Carpal Tunnel Syndrome (CTS) is a peripheral mono-neuropathy of the upper limb, caused by
compression of the median nerve as it passes through the carpal tunnel into the wrist. In the carpal tunnel the
median nerve lies immediately beneath the palmaris longus tendon and anterior to the flexor tendons.
Conditions which decrease the tunnel’s size, or swell the structures contained within it, compress the
median nerve against the transverse ligament bounding the tunnel’s roof. Such circumstances can arise
traumatically, congenitally, or due to systemic or inflammatory effects.
CTS is produced by compression of the median nerve within the tunnel. The exact cause of the
compression is difficult to determine, but thickening of the synovial sheaths of the flexor tendons or arthritic
changes in the carpal bones are thought to be responsible in many cases. Known causes of CTS include diabetes
mellitus, rheumatoid arthritis, acromegaly, hypothyroidism, pregnancy and tenosynovitis. CTS can also develop
as a complication of distal radius fractures (See @ http://www.eorthopod.com/content/carpal-tunnelsyndrome-as-a-complication-of-wrist-fracture).
Certain intrinsic predisposing factors of CTS are female gender, pregnancy, diabetes, and rheumatoid
arthritis. A clinical diagnosis of CTS consists of the patient’s history and a physical examination. Typical
symptoms are pain and paresthesias of the palmar radial hand, which is worse at night and often awakens the
patient from sleep. Physical examination may reveal thenar wasting, intrinsic muscle weakness, and impaired
sensation in the distribution of the median nerve.
Clinically, the syndrome consists of a burning pain or “pins and needles” along the distribution of the
median nerve to the lateral three and a half fingers and weakness of the thenar muscles as well. As would be
expected, no paresthesia occurs over the thenar eminence because this area of skin is supplied by the palmar
cutaneous branch of the median nerve, which passes superficially to the flexor retinaculum. The condition is
dramatically relieved by decompressing the tunnel by making a longitudinal incision through the flexor
retinaculum.
The history is of gradual onset of numbness and tingling in the median nerve distribution of the hand.
This most common type of peripheral mononeuropathy of the upper limb can be related to occupational
factors (See @ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145125/?tool=pubmed).
More to read!
Ono S, Clapham PJ, Chung KC. Optimal management of carpal tunnel syndrome. Int J Gen Med. 2010;3:
255-261.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2934608/?tool=pubmed
Kachare M, Hahn E Jr, Granick MS. Carpal tunnel syndrome. Eplasty. 2013;13:ic8. Epub 2013 Jan 18.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3554258/pdf/eplasty13ic08.pdf
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
Figure 5. Carpal tunnel
http://www.ama-assn.org/ama/pub/physician-resources/patient-education-materials/atlas-of-human-body/hand-carpal-tunnel.page
Ulnar Nerve Injuries
The ulnar nerve is most commonly injured at the elbow, where it lies behind the medial epicondyle, and
at the wrist, where it lies with the ulnar artery in front of the flexor retinaculum. The injuries at the elbow are
usually associated with fractures of the medial epicondyle. The superficial position of the nerve at the wrist
makes it vulnerable to damage from cuts and stab wounds. The clinical findings in injury to the ulnar nerve are
as follows.
Injuries to the Ulnar Nerve at the Elbow
(Cubital Tunnel Syndrome)
Cubital Tunnel is a fibro-osseus tunnel between the medial epicondyle and flexor carpi ulnaris. The floor of the
cubital tunnel is formed by the medial collateral ligament of the elbow. Compression of the ulnar nerve at the
elbow, or cubital tunnel syndrome, is the second most common peripheral nerve compression syndrome in the
upper extremity. Diagnosis is made through a good history and physical examination. Electrodiagnostic testing
can confirm the diagnosis and severity of injury to the nerve. The ulnar nerve proper travels the following
course:
 Originates in the axilla from the medial cord of the brachial plexus, with contributions from the C8-T1 nerve
roots
 Travels posterior to the medial intermuscular septum, anterior to the medial head of the triceps
 Through the cubital tunnel (defined later)
 Dives into the forearm between the 2 heads of the FCU (flexor carpi ulnaris)
 Travels between the flexor carpi ulnaris and flexor digitorum profundus into the forearm
 Travels through Guyon canal at the wrist
 Terminates in the hand as motor and sensory branches
 Sensory: ulnar digital nerve to the ring finger, radial and ulnar digital nerves to the small finger
 Motor: deep motor branch to the intrinsic muscles of the hand
Motor
Patients with cubital tunnel syndrome present with paresthesias over the small and ring fingers.
Paresthesias present early in the disease and progress to motor dysfunction as the compression of the nerve
becomes more severe and chronic. Intrinsic muscle weakness, as well as, weakness of flexor digitorum
profoundus of small and ring fingers can be seen in more advanced disease, which presents as clawing.
The flexor carpi ulnaris and the medial half of the flexor digitorum profundus muscles are paralyzed. The
paralysis of the flexor carpi ulnaris can be observed by asking the patient to make a tightly clenched fist.
Normally, the synergistic action of the flexor carpi ulnaris tendon can be observed as it passes to the pisiform
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
bone; the tightening of the tendon will be absent if the muscle is paralyzed. The profundus tendons to the ring
and little fingers will be functionless, and the terminal phalanges of these fingers are therefore not capable of
being markedly flexed. Flexion of the wrist joint will result in abduction, owing to paralysis of the flexor carpi
ulnaris.
The medial border of the front of the forearm will show flattening, owing to the wasting of the
underlying ulnaris and profundus muscles. The small muscles of the hand will be paralyzed, except the muscles
of the thenar eminence and the first two lumbricals, which are supplied by the median nerve. The patient is
unable to adduct and abduct the fingers and consequently is unable to grip a piece of paper placed between
the fingers. Remember that the extensor digitorum can abduct the fingers to a small extent, but only when the
metacarpophalangeal joints are hyperextended. It is impossible to adduct the thumb because the adductor
pollicis muscle is paralyzed. If the patient is asked to grip a piece of paper between the thumb and the
index finger, he or she does so by strongly contracting the flexor pollicis longus and flexing the terminal phalanx
(Froment’s sign). http://en.wikipedia.org/wiki/Froment%27s_sign.
Figure 6. Froment’s sign in ulnar nerve palsy
http://www.mims.com/resources/drugs/common/CP0042.gif
The metacarpophalangeal joints become hyperextended because of the paralysis of the lumbrical and
interosseous muscles, which normally flex these joints. Because the first and second lumbricals are not
paralyzed (they are supplied by the median nerve), the hyperextension of the metacarpophalangeal joints is
most prominent in the fourth and fifth fingers. The interphalangeal joints are flexed, owing again to the
paralysis of the lumbrical and interosseous muscles, which normally extend these joints through the extensor
expansion. The flexion deformity at the interphalangeal joints of the fourth and fifth fingers is obvious because
the first and second lumbrical muscles of the index and middle fingers are not paralyzed. In longstanding cases
the hand assumes the characteristic “claw” deformity (main en griffe). Wasting of the paralyzed muscles results
in flattening of the hypothenar eminence and loss of the convex curve to the medial border of the hand.
Examination of the dorsum of the hand will show hollowing between the metacarpal bones caused by wasting
of the dorsal interosseous muscles.
Sensory
Loss of skin sensation will be observed over the anterior and posterior surfaces of the medial third of the hand
and the medial one and a half fingers.
Vasomotor Changes
The skin areas involved in sensory loss are warmer and drier than normal because of the arteriolar dilatation
and absence of sweating resulting from loss of sympathetic control.
Kroonen LT. Cubital tunnel syndrome. Orthop Clin North Am. 2012 Oct;43(4):475-486.
Wojewnik B, Bindra R. Cubital tunnel syndrome - Review of current literature on causes, diagnosis and
treatment. J Hand Microsurg. 2009 Dec;1(2):76-81.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3453029/pdf/12593_2009_Article_20.pdf
http://bonefix.co.nz/portals/160/files/Ulnar%20nerve%20entrapment.pdf
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
Injuries to the Ulnar Nerve at the Wrist
Motor: The small muscles of the hand will be paralyzed and show wasting, except for the muscles of the thenar
eminence and the first two lumbricals. The clawhand is much more obvious in wrist lesions because the flexor
digitorum profundus muscle is not paralyzed, and marked flexion of the terminal phalanges occurs.
Sensory: The main ulnar nerve and its palmar cutaneous branch are usually severed; the posterior cutaneous
branch, which arises from the ulnar nerve trunk about 2.5 in. (6.25 cm) above the pisiform bone, is usually
unaffected. The sensory loss will therefore be confined to the palmar surface of the medial third of the hand
and the medial one and a half fingers and to the dorsal aspects of the middle and distal phalanges of
the same fingers.
Vasomotor and trophic changes: These are the same as those described for injuries at the elbow. It is
important to remember that with ulnar nerve injuries, the higher the lesion is the less obvious is the clawing
deformity of the hand.
Guyon’s canal syndrome & Ulnar paradox
Ulnar nerve entrapment at the wrist
Sparing of flexor digitorum profoundus is seen with more distal compression, such as seen at Guyon’s canal and
can help with differential diagnosis. This flexor digitorum profundus sparing is called ulnar paradox, which
means that the more distal the lesion is on the ulnar nerve the less clawing is noted due to decreased
involvement of flexor digitorum profoundus with more distal lesions.
Palmaris brevis forms the roof of the Guyon canal. Flexor carpi ulnaris, hamate and pisiforme bones are other
structures forming the canal. The ulnar artery and ulnar nerve, venae communicantes travel in the Guyon canal.
http://www.pncl.co.uk/~belcher/teaching/Guyon%27s%20release.pdf
Unlike median nerve injuries, lesions of the ulnar nerve leave a relatively efficient hand. The sensation
over the lateral part of the hand is intact, and the pincer-like action of the thumb and index finger is reasonably
good, although there is some weakness, owing to loss of the adductor pollicis.
Figures 7 & 8. “Claw hand deformity” in ulnar nerve injuries
http://2hmnzava.blogspot.com/2010/04/from-orthopaedic-dictionary.html
http://www.pathopedia-india.com/clawhand.JPG
CLINICAL ANATOMY OF THE BRACHIAL PLEXUS BLOCK
In the neck, the brachial plexus occupies the lower part of the posterior triangle. It lies below and
anterior to a line connecting the cricoid cartilage of the larynx to the midpoint of the clavicle. In the axilla, the
brachial plexus and its branches are arranged withinthe axillary sheath around the axillary artery, which can be
palpated.
Injection of an anesthetic solution into or immediately surrounding the axillary sheath interrupts
conduction of impulses of peripheral nerves and produces anesthesia of the structures supplied by the
branches of the cords of the plexus. Because the axillary sheath encloses the axillary vessels and the brachial
plexus, a brachial plexus nerve block can easily be obtained. The distal part of the sheath is closed with finger
pressure, and a syringe needle is inserted into the proximal part of the sheath. Sensation is blocked in all deep
structures of the upper limb and the skin distal to the middle of the arm. The brachial plexus can be
anesthetized using a number of approaches, including an interscalene, supraclavicular, and axillary approach or
block. The axillary nerve block is a common technique used.
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
Axillary Block
Procedure: With the arm abducted to an angle greater than 90°, the axillary artery within the axillary sheath
may be palpated high up in the axilla. The artery is compressed, and a blocking needle is inserted just proximal
to the point of compression into the axillary sheath. The disadvantage of this approach is the difficulty in
blocking the musculocutaneous nerve. The object of compressing the artery distal to the point of injection is to
close off the axillary sheath distally so that the anesthetic agent may rise in the sheath to the
musculocutaneous nerve.
Anatomy of complications: The close relationship of the axillary vessels to the brachial plexus within the
axillary sheath means that vessel puncture and hematoma formation may occur.
Other block techniques
Interscalene block
The blocking needle is inserted into the interval between the scalene muscles, and the roots of the upper part
of the brachial plexus can be blocked.
Supraclavicular Block
Procedure: The trunks of the brachial plexus can be blocked as they cross the first rib and enter the axilla.
Infraclavicular Block
The middle of the clavicle is identified. A blocking needle is inserted 1 in. (2.5 cm) inferior to the middle of the
clavicle.
Musculocutaneous Nerve Block
Repair of lacerations on the lateral border of the forearm
Median Nerve Block
Area of anesthesia: The skin on the lateral half of the palm, the palmar aspect of the lateral three and a half
fingers, including the nail beds on the dorsum.
Indications: Repair of lacerations of the palm and fingers
Ulnar Nerve Block
Indications: Repair of lacerations of the hand and fingers
Radial Nerve Block
Indications: Repair of lacerations of the hand:
Procedures: These involve the following:
Suggested links:
http://download.videohelp.com/vitualis/med/uppnn.htm
http://anatomy.uams.edu/anatomyhtml/nerves_upperlimb.html
http://anatomyguy.com/path-tracing-vessels-and-nerves-of-the-upper-limb
SHOULDER
Anastomosis around the shoulder
The scapular anastomosis system is a system connecting each subclavian artery and the corresponding
axillary artery, forming an anastomosis around the scapula. It allows blood to flow past the joint regardless of
the position of the arm. The system is to anastomose or connect the first part of the subclavian artery with the
third part of the axillary artery providing a collateral circulation. This collateral circulation allows for blood to
continue circulating if the subclavian is obstructed. The subscapular artery, a branch of the third part of the
axillary artery is a key vessel in this anastomosis system. The two other arteries of the third part of the axillary
artery; the posterior circumflex humeral artery and anterior circumflex humeral artery also anastomese with
each other, and the posterior circumflex humeral artery has anastomosis with profunda brachii ( a branch of
the brachial artery), and branches of the axillary and subclavian arteries.
Quadrangular Space Syndrome
Quadrilateral space syndrome is a clinical syndrome resulting from compression of the axillary nerve and
posterior circumflex humeral artery in the quadrilateral space. The quadrilateral space is an anatomic space in
the upper arm bounded by the long head of the triceps, the teres minor and teres major muscles, and the
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
cortex of the humerus. The passage of the axillary nerve backward from the axilla through the quadrangular
space makes it particularly vulnerable here to downward displacement of the humeral head in shoulder
dislocations or fractures of the surgical neck of the humerus. Paralysis of the deltoid and teres minor muscles
results. The cutaneous branches of the axillary nerve, including the upper lateral cutaneous nerve of the arm,
are functionless, and consequently there is a loss of skin sensation over the lower half of the deltoid muscle.
Rotator Cuff Tendinitis
The rotator cuff, consisting of the tendons of the subscapularis,supraspinatus, infraspinatus, and teres
minor muscles, which are fused to the underlying capsule of the shoulder joint, plays an important role in
stabilizing the shoulder joint. Lesions of the cuff are a common cause of pain in the shoulder region. Excessive
overhead activity of the upper limb may be the cause of tendinitis, although many cases appear spontaneously.
During abduction of the shoulder joint, the supraspinatus tendon is exposed to friction against the acromion.
Under normal conditions, the amount of friction is reduced to a minimum by the large subacromial bursa,
which extends laterally beneath the deltoid. Degenerative changes in the bursa are followed by degenerative
changes in the underlying supraspinatus tendon, and these may extend into the other tendons of the rotator
cuff. Clinically, the condition is known as subacromial bursitis, supraspinatus tendinitis, or pericapsulitis. It is
characterized by the presence of a spasm of pain in the middle range of abduction, when the diseased area
impinges on the acromion.
Rupture of the Supraspinatus Tendon
In advanced cases of rotator cuff tendinitis, the necrotic supraspinatus tendon can become calcified or
rupture. Rupture of the tendon seriously interferes with the normal abduction movement of the shoulder joint.
The main function of the supraspinatus muscle is to hold the head of the humerus in the glenoid fossa at
the commencement of abduction. The patient with a ruptured supraspinatus tendon is unable to initiate
abduction of the arm. However, if the arm is passively assisted for the first 15° of abduction, the deltoid can
then take over and complete the movement to a right angle.
ANTERIOR ASPECT OF THE FOREARM & CUBITAL FOSSA
Pronator Syndrome
Pronator syndrome, a nerve entrapment syndrome, is caused by compression of the median nerve near the
elbow. The nerve may be compressed between the heads of the pronator teres as a result of trauma, muscular
hypertrophy, or fibrous bands. Individuals with this syndrome are first seen clinically with pain and tenderness
in the proximal aspect of the anterior forearm and hypesthesia of palmar aspects of the radial three and half
digits and adjacent palm. Symptoms often follow activities that involve repeated pronation.
Anterior interosseous nerve syndrome
The anterior interosseous nerve ( an entirely motor branch of the median nerve) provides motor innervation to
the flexor pollicis longus (FPL), flexor digitorum profundus (FDP) to the index and sometimes middle fingers,
and to the pronator quadratus (PQ). Paralysis of these muscles from a complete nerve palsy will result in a
pinch deformity, though weakness of pronation may be masked by the concurrent action of the pronator teres
(PT). A case report @ http://www.sma.org.sg/smj/4412/4412cr1.pdf
Communications Between Median and Ulnar Nerves
Occasionally, communications occur between the median and the ulnar nerves in the forearm. These branches
are usually represented by slender nerves, but the communications are important clinically because even with a
complete lesion of the median nerve, some muscles may not be paralyzed. This may lead to an erroneous
conclusion that the median nerve has not been damaged.
Measuring Pulse Rate
The common place for measuring the pulse rate is where the radial artery lies on the anterior surface of the
distal end of the radius, proximal to the wrist, between the tendons of the flexor carpi radialis and
brachioradialis. Here the artery is covered by only fascia and skin. The artery can be compressed against the
distal end of the radius, where it lies between the tendons of the flexor carpi radialis and abductor pollicis
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Dr. Kaan Yücel
http://yeditepeanatomy1.org
Clinical anatomy of the upper limb
longus. When measuring the radial pulse rate, the pulp of the thumb should not be used because it has its own
pulse, which could obscure the patient's pulse. If a pulse cannot be felt, try the other wrist because an aberrant
radial artery on one side may make the pulse difficult to palpate. A radial pulse may also be felt by pressing
lightly in the anatomical snuff box between the extensor pollicus longus and brevis muscles.
POSTERIOR ASPECT OF THE FOREARM & HAND
Venipuncture
In many patients, venous access is necessary for obtaining blood for laboratory testing and
administering fluid and intravenous drugs. The ideal sites for venous access are typically in the cubital fossa and
in the cephalic vein adjacent to the anatomical snuffbox. The veins are simply distended by use of a tourniquet.
A tourniquet should be applied enough to allow the veins to become prominent.
In the subcutaneous tissue, the median cubital vein most commonly running obliquely across the
cubital fossa, connecting the cephalic vein of the forearm and basilic vein of the arm, provides an advantageous
site for venipuncture. In about one fifth of the population, a median antebrachial vein bifurcates into median
cephalic and median basilic veins, which replace the diagonal median cubital vein. For straightforward blood
tests these veins are usually the preferred site as they are easily palpated. The cephalic vein is generally the
preferred site for short-term intravenous cannula.
Anatomical snuffbox
The anatomical snuffbox is an important clinical region. When the hand is in ulnar deviation, the
scaphoid becomes palpable within the snuffbox. This position enables the physician to palpate the bone to
assess for a fracture. The pulse of the radial artery can also be felt in the snuffbox. The "anatomical snuffbox" is
a term given to the triangular depression formed on the posterolateral side of the wrist and metacarpal I by the
extensor tendons passing into the thumb. Historically, ground tobacco (snuff) was placed in this depression
before being inhaled into the nose. The base of the triangle is at the wrist and the apex is directed into the
thumb. The impression is most apparent when the thumb is extended:
 lateral border is formed by the tendons of the abductor pollicis longus and extensor pollicis brevis;
 medial border is formed by the tendon of the extensor pollicis longus;
 floor of the impression is formed by the scaphoid and trapezium, and the distal ends of the tendons of the
extensor carpi radialis longus and extensor carpi radialis brevis.
The radial artery passes obliquely through the anatomical snuffbox, deep to the extensor tendons of the thumb
and lies adjacent to the scaphoid and trapezium.
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